In recent years, a UI (User Interface) that uses a touch panel is becoming widespread as means for enabling anyone to easily perform an input/output operation of information. For example, by performing a gesture of screen scrolling by directly dragging the screen, an operation process associated with the gesture can be performed. By associating a gesture with an operation process that is easily and intuitively imagined by a user from the gesture, an input operation by the gesture can be facilitated.
For example, in Patent Literature 1, an input device is disclosed that performs input processes that are based on a plurality of different input modes, according to the degree of pressing or the state of sliding of an operating object such as a finger with respect to a display screen. By using such an input device, a user is allowed to change the motion of a finger on the display screen to thereby cause an input process corresponding to each motion to be performed. As a gesture performed by a user in a state where a finger is in contact with the screen, there is a drag operation of moving the finger up or down or left or right on the screen, for example. An operation of performing screen scrolling or an operation of changing the zoom rate of an image displayed on the screen may be associated with the drag operation, for example.